基于模组解耦控制的高调制比混合型MMC电容优化方法  

Module decoupling control based capacitance optimization for hybridmodular multi-level converter with high modulation index

作　　者：孙标 路茂增 张存山[1] 马新喜 周琳智 SUN Biao;LU Maozeng;ZHANG Cunshan;MA Xinxi;ZHOU Linzhi(School of Electrical and Electronic Engineering,Shandong University of Technology,Zibo 255049,China)

机构地区：[1]山东理工大学电气与电子工程学院,山东淄博255049

出　　处：《电力工程技术》2023年第5期148-157,共10页Electric Power Engineering Technology

基　　金：山东省自然科学基金青年资助项目(ZR2020QE215)。

摘　　要：高调制比混合型模块化多电平换流器(modular multi-level converter,MMC)子模块电容的均压控制方法借鉴半桥型MMC,全桥及半桥子模块电容的充放电行为存在强耦合,导致半桥子模块电容电压波动率较小,给电容值的优化带来挑战。为此,文中首先计算高调制比下两类子模块的电容电压波动率,以明确半桥子模块电容值的优化空间。进一步,提出全桥及半桥模组平均开关函数的设计原则,考虑子模块电容电压瞬时最大值的约束,实现半桥子模块电容值的优化。然后,在现有MMC基本控制框架下,提出基于模组解耦的控制策略,实现电容电压动态的准确控制。最后,在MATLAB/Simulink中搭建混合型MMC的仿真模型,对所提电容优化方法进行验证。仿真结果表明:所提电容优化方法不仅可以实现对全桥及半桥子模块电容电压直流分量和纹波分量的控制,还可降低半桥子模块电容值。Hybrid modular multi-level converter(MMC)consisting can operate with a high modulation index,and it borrows the capacitor voltage balance method from half-bridge MMC.Thus,a strong coupling effect occurs in the charging behaviours of full bridge sub-modules(FBSMs)and half bridge sub-modules(HBSMs),which causes a low volatility of the ripple voltage of HBSMs′capacitors and challenges for its capacitance optimization.To address this issue,the ripple coefficients of HBSMs′and FBSMs′capacitor voltages are calculated for MMC operating with a high modulation index quantitatively.The optimize of HBSMs′capacitance can be clarified.Then,design principles of the optimal HBSMs′and FBSMs′average switching functions are explored.Hence,the optimization of HBSMs′capacitance is achieved with the constraint of the maximal value of sub-modules′instantaneous capacitor voltages.Further,under the conventional basic control framework of MMC,a control strategy based on module decoupling control which can regulate the dynamics of capacitor voltage accurately is proposed.Finally,hybrid MMC operating is modeled with MATLAB/Simulink.The proposed capacitor optimization method is verified.The simulation results show that the DC component and ripple component of capacitors′voltages can be regulated accurately,and the capacitance of HBSMs can be reduced effectively.

关 键 词：混合型模块化多电平换流器(MMC) 高调制比 电压纹波 解耦控制 电容优化 模组平均开关函数 

分 类 号：TM72[电气工程—电力系统及自动化]